Analysis of current unbalance in transmission systems with short lines

作者：Kalyuzhny Aaron^*; Kushnir Gregory

来源：IEEE Transactions on Power Delivery, 2007, 22(2): 1040-1048.

DOI：10.1109/TPWRD.2006.883011

• asymmetry
• current unbalance
• magnetic field
• sequence currents
• three-phase load flow

The analysis of current unbalance in power systems with short transmission lines is presented. Measurements in the Israel Electric Transmission System as well as numerical simulations of three-phase load flow have revealed lines with a high level of current unbalance. It is found that significant current unbalance on short transmission lines may take place due to the following reasons:
inherent asymmetry of untransposed transmission lines;
presence of line traps used for power-line carriers (PLC);
electromagnetic coupling between lines on double-circuit towers;
superposition of current symmetrical components in lines under light loading.
It is shown that the current asymmetry may lead to overcurrents in individual phases of transmission lines as well as to growth of the magnetic field in proximity of the lines.

• 出版日期2007-4